WASHINGTON  Iraqi insurgents are teaching recruits sophisticated sniper techniques for targeting U.S. troops that include singling out engineers, medics and chaplains, according to training material obtained by U.S. military intelligence.

The insurgent sniper training manual was posted on the Internet. Among its tips: "Killing doctors and chaplains is suggested as a means of psychological warfare."

Army Capt. Matt Hasson of Central Command confirmed the manual's authenticity but wouldn't talk about specifics.

The threat of sniper fire is greatest in urban areas because shooters have more hiding places. That's a concern for U.S. forces as more troops enter Baghdad to combat escalating violence.

In Ramadi, west of Baghdad, Army Col. Sean MacFarland disclosed plans this month to level a dozen buildings used as hiding places by snipers and bombers.

Combat troops don't always report sniper deaths as such to prevent insurgents from learning that an attack succeeded, says Army Maj. John Morgan, a spokesman for U.S. forces in Baghdad. Through November 2005, when the Pentagon last reported a sniper fatality, the Army had attributed 28 of 2,100 U.S. deaths to snipers.

This year, snipers have killed at least 16 U.S. troops, according to news accounts or information posted on blogs by troops' family members. None of these fatalities was blamed on sniper fire in official reports; the deaths were attributed to "small arms fire" or "combat operations."

The insurgent manual says snipers should target U.S. officers because they are hard to replace, tank drivers because their death could immobilize a tank crew, and communications officers because their death could delay calls for reinforcements.

Translated into English by U.S. intelligence, the manual advises snipers to avoid large groups of soldiers "unless you are sure of your ability to kill them and escape." It ranks Iraqi government forces as lower-priority targets who can be attacked by less well-trained combat brigades.

U.S. intelligence discovered the training manual in May 2005 on a website that appears to be no longer functioning.

The Army's intelligence branch at the Training and Doctrine Command at Fort Leavenworth in Kansas studied the sniper problem last year out of concern that it wasn't getting enough attention. Three reports were distributed to officers in charge of training troops for duty in Iraq.

"Snipers were — in our estimation — a threat that was not being robustly portrayed in mission rehearsal exercises," command spokesman Harvey Perritt said in an e-mail response to questions.

The Army's sniper study and a follow-up last November observed that insurgent snipers are "well-trained," often work in two-man teams, can shoot around troops' body armor and have easy access to weapons from stockpiles left by the former regime of Saddam Hussein.